Resolve "Nav eval > Ultimate progress bar ARIA"

What does this MR do and why?

Add aria-hidden="true" to Ultimate progress bar. Note that this is added to the direct parent and not the div with role="progressbar" because this isn't changed at the component level.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Accessibility tree before	Accessibility tree after

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

To get the widget to appear…

1. In line 156 of gitlab/app/assets/javascripts/super_sidebar/components/super_sidebar.vue, change <div v-if="showTrialStatusWidget" to <div v-if="sidebarData.is_logged_in".
2. Changes lines 19–29 of gitlab/ee/app/assets/javascripts/contextual_sidebar/components/trial_status_widget.vue to:

    trialDaysUsed: { default: 5 },
    trialDuration: { default: 30 },
    navIconImagePath: {
      default:
        '/assets/illustrations/golden_tanuki-a88ad492b973a0ea6be2316b12aeb3a76ee4e926b3b217dc26d01a57033c9948.svg',
    },
    percentageComplete: { default: 10 },
    // eslint-disable-next-line @gitlab/require-i18n-strings
    planName: { default: 'Ultimate Trial' },
    plansHref: { default: '/asdf' },```

3. Inspect the accessibility tree.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #426747 (closed)